Sundial



May 17,-1927. 1,629,238

s. TERRAZ sun DIAL Filed Sept. 7. 1926 2 Sheets-Sheet 1 Inventor Attorney May 17, 1927.

S. TERRAZ SUN DIAL Filed Sept. '7. 1926 2 Sheets-Sheet 2 I v Inventor awn ozone}: Z 67782 M m Attorney Patented May 17,1927.

tam-sin SYMPI-IORIAN TERRAZ; or WOR ESTER,nassnenesmrs, assrenon ro THE or Assunrrron "COLLEGE, or wononsrna, MASSACHUSETTS.

, sunnr rn Apphcationfled September 7, 1926. Seria1 No, 134,10 L' I The present invention has reference to an improved sun dial and it has more particular. reference to one of the well .known equino ctial type. V p j The present invention is built upon what is believed tobe an entirely new principle and it includes means not to befound in ordinary instruments of this class, the means being such as toupro'vi de both the time of the sun and the corresponding time indicated upon mechanical clocks, to the nearest minute, for all da s of theyear and any latitude, on eitherof the two hemispheres, 'The construction for accomplishing'the, desired method of reading the time will become apparent from the accompanying drawings, in which':'.. j, j I Fi gure 1 is a perspective, looking at one side of the im rtvedstrucmre; v V

Fig. 2 is a perspective view,,looking' at the front of the structure. H h

Fig. 3, is a perspective View of one of the details hereinafter referred to. s the equinocan dine.

parts, a base, a fork adjustably mo'u'nted' formation.

The base, which is represented generally by the reference character 1, is composed of a sturdy bronze column formed integral with a circular bottom. The structure is centrally bored for slidable reception of a vertical iron rod 2 which is previously set in a cement anchor and extends upwardly through the bore in the circular bottom 3 and a tubular standard 4, set screws 5 being employed to maintain these parts in adjust ed position. The top of the standard is bifurcated and the furcations are represented by the reference character 6. On one side just below-these furcations are outstanding parallel ears 7 constituting a mounting for an adjusting set screw 8.

The fork, as the name implies, is generally designated by thejreference character 9 and this includes opposed arms 10 connected with a special casting including a plate-like portion 11 disposed for movement between the turcations 6 and connected thereto by a pivot and adjusting screw 12. The casting is provided with outstanding spaced lugs 13 which serve a purpose to be hereinafter decalibrated hora'l receptive head of segmental Briefly, the inventionfcomprises four scribedandthej free ends: of the arms are I provided with indicating wire 14.

TRUSTEES Thei'orl; is connected to the head gener-,

ally designated by. the reference character -15. Thishead is of segmental format-ion,

being approximately tl1ree qua1'ters of acircle. The inner peripheral :t'aceof the stay.

tionary part 1-6 is providedwith properly .3

arranged graduations 17 with which the shadow'cooperates. The inner face of this 7 part 16 is constructed to accommodate aseg-g mental relatively adjustable rack 189mm ably mounted in the guide channel or groove shown in the drawing.

whereby it: may be bodilyadjusted with re- The inner peripheral face of this rack is computationof time. thegraduated horal receptive surfaces, of

16 represent sun time tions, 21 clock tinie;

by theothel graduafor all, it is correctly adjusted to thelocal meridian of that particular latitude, the correct clock time may be obtained to a very minute'degree by merely turning the movable dial a given number of minutes either to the right or left of thefixed dial,

, a knob 191s provided and this knob i aturn provided with a pinion 20, the teethf of which mesh with; the teeth on the rack,

spct to the relatively stationary partjl'5,

the relatively"movable parts ltijand 17, it is to besta'tedthat graduatio'ns 17 of the part.

according to the directions of the local chart of equation of time. As explained, this chart must be so computed as to combine the general delays or advances between the sun and the clocks on the different seasons of the year. ence of latitude between-a given place and the central meridian, setting the standard time of the timebelt. Then too, the local chart of the equation must eventually take into the'account of day-light saving, adopted in many States during the summer months.

7100 Itinust moreover, combine the difier- With a little care and patience, any one can compute a correct chart of the equation of time adapted to a given locality. Once this chart has been calculated, it will serve as an indispensable and reliableguide whenever it is desired to set a watch or clock by the sun time. By considering the chart for a given day of the year, the chart will indicate that on a particular day when it is noon time by the sun, the clock or watch should indicate, for instance, 12.15 oclock.

By moving the adjustable part of the apparatus, fifteen minutes to the right of the fixed dial, the position of the shadow cast on the movable dial will show thecorrect clock time any moment of the given day for several days in succession without further adjustment of the dial.

,The dial represents the fourth part of the circumference and is graduated from O to 90. As it is fixed to the handle of the fork, and as'the fork may be moved up and down by means of the pin on which it turns, and which is set at the top of the, pedestal, any motion of fork causes the latitude dial to turn, and the number of degrees it turns is shown by means of the fixed pointer. When the fork is raised-so as to give the steel wire,"or rod, ahorizontal position, the latitude dial indicates 0, which is the latitude of the equator.

If the fork is lowered so as to bring the steel wire into a' vertical position, the latitude dial points to 90 which is the latitude of the earths pole.

It is believed that by considering the description in connection with the illustration made in'the drawings, a clear understanding of the invention and itsadvantages will be had. Consequently, a more lengthy description is thought unnecessary. r

Minor changes coming within the field of invegition claimed may be resorted to if desire Having thus described my invention, what I claim as new i s 1. In a sun dial, a base, a standard, a fork adj ustably mounted upon a horizontalfpivot at the upper end of the standard, the arms of the forks being disposed opposite each other and being swingable in a vertical plane about said pivot, an equinoctial dial structure disposed centrally between and in a plane transverse to the plane of the arms of the fork and secured thereto, said structure including a channel-shaped arcuate fixedpart, a rack of a shape corresponding to said part, and mounted for movement circumferentially in said channel, means for adjusting the rack, both of said parts being provided on their inner surfaces with cooperating graduations, and there being an indicator mounted on and between the free end'portions of the fork cooperable with said graduations.

2. In an equinoctialsun dial, a base, a standard rising from said base, a horizontal pivot at the'top of the standard, a fork mounted on the horizontal pivot, said fork including spaced arms at the outer ends of and extending between which is mounted an indicator, a head, and means for mounting head including concentric arcuate parts, one of which is fixed to said fork and the other one of which is relatively movable with respect to the fixed part about their common the head in and transverse to said fork, said I 

